The present invention relates generally to a electrosurgical probe systems and particularly to such a system that includes an array of radio frequency (RF) electrodes with controllable, movable, non-conductive sleeves.
The field of electrosurgery includes a number of loosely related surgical techniques which have in common the application of electrical energy to modify the structure or integrity of patient tissue. Electrosurgical procedures usually operate through the application of very high frequency currents to cut or ablate tissue structures, where the operation can be monopolar or bipolar. Monopolar techniques rely on external grounding of the patient, where the surgical device defines only a single electrode pole. Bipolar devices comprise both electrodes for the application of current between their surfaces.
Electrosurgical procedures and techniques are particularly advantageous since they generally reduce patient bleeding and trauma associated with cutting operations. Additionally, electrosurgical ablation procedures, where tissue surfaces and volume may be reshaped, cannot be duplicated through other treatment modalities.
The use of electrosurgical procedures in electrically conductive environments, however, can be problematic. For example, many procedures require flushing of the region to be treated with isotonic saline (also referred to as normal saline), both to maintain an isotonic environment and to keep the field of view clear. The presence of saline, which is a highly conductive electrolyte, can cause shorting of the electrosurgical electrode in both monopolar and bipolar modes. Such shorting causes unnecessary heating in the treatment environment and can further cause non-specific tissue destruction.
Prostate diseases, such as prostate cancer and benign prostatic hypertrophy (BPH), can cause enlargement of the prostate which in turn causes a narrowing of the urethra adjacent the prostate caused by swelling of the surrounding tissue. Such narrowing can cause difficulty in urination, resulting in discomfort and exposing the patient to further complications. A variety of methods have been proposed for treating enlarged prostates. Generally, the methods rely on either reducing the prostatic mass to lessen pressure on the urethra or resecting prostatic tissue adjacent the urethra in order to increase the luminal area for passing urine. The first group of methods include various protocols for directing energy, including microwave radiation, RF energy, and laser energy, to induce an increase in tissue temperature within a defined volume of the prostate. Such an increase in tissue temperature, often referred to as xe2x80x9cthermotherapyxe2x80x9d, will be maintained at a temperature and for a time sufficient to cause necrosis of the treated prostatic tissue, with the necrosed tissue being subsequently sloughed off or reabsorbed into the surrounding tissue mass. Such sloughing off or reabsorption of the necrosed tissue, in turn, will cause size reduction of the prostate, relieving the symptoms of BPH. The latter group of methods includes the use of endoscopes introduced through the urethra which allow for controlled tissue resection.
Of particular interest to the present invention are invasive, catheter-like devices that are inserted into prostatic tissue. An example of such a device is described in U.S. Pat. No. 5,964,727 to Edwards et al., the disclosure of which is incorporated herein by reference. The Edwards et al. device includes a catheter having a stylet guide for directing a flexible stylet outward through a stylet port and through intervening tissue at a preselected, adjustable angle to a target tissue. In one embodiment, the stylet is an RF electrode with a non-conductive sleeve which is axially movable on the electrode to expose a selected portion of the electrode surface in the target tissue. However, the Edwards et al. device suffers from the drawback of lack of control of movement of the non-conductive sleeve.
The present invention seeks to provide an improved electrosurgical system that includes an array of RF electrodes (stylets) with controllable, movable, non-conductive sleeves. The electrosurgical system preferably includes an actuator system that can move the stylets and sheaths independently of each other. In this manner, the actuator system has two modes of operation. In a first mode, the actuator system moves the stylets together with the sheaths. In a second mode, the actuator system slides the stylets relative to the sheaths, thereby exposing more or less of the stylets as required for the electrosurgery procedure. An optical sensor system is preferably in electrical communication with the actuator system in a closed loop control system. The actuator system controls movement of the stylets and sheaths in accordance with feedback received from the optical sensor system, and commands received from a treatment plan, such as from treatment software.
It is noted that although the electrosurgical system of the present invention is described for use with prostate treatment, nevertheless the system of the present invention is not limited to the prostate but may be used for any kind of suitable body organ or cavity.
There is thus provided in accordance with a preferred embodiment of the present invention an electrosurgical system including at least one electrically insulating sheath, at least one electrically conductive stylet slidingly disposed in the at least one sheath, the at least one stylet being connectable to and energizable by an electrical source, an actuator system connected to the at least one stylet and connected to the at least one sheath independently of the at least one stylet, the actuator system having two modes of operation, wherein in a first mode the actuator system moves the at least one stylet together with the at least one sheath, and in a second mode the actuator system slides the at least one stylet relative to the at least one sheath.
In accordance with a preferred embodiment of the present invention the actuator system includes a first tab attached to the at least one stylet, a second tab attached to the at least one sheath, an actuator, and a plurality of arms attached to and movable by the actuator, the arms being selectively attachable to the first and second tabs.
Further in accordance with a preferred embodiment of the present invention a plurality of the stylets and sheaths are provided, wherein the first tab is attached to a pair of the stylets, and the second tab is attached to a pair of the sheaths, the pair of stylets being electrically energized as a bipolar electrode.
Still further in accordance with a preferred embodiment of the present invention the at least one stylet and sheath are slidingly mounted in a frame, and the plurality of arms are hingedly attached to the frame at a pivot, the plurality of arms being selectively swingable about the pivot away from and towards the first and second tabs.
Additionally in accordance with a preferred embodiment of the present invention the frame is attached to a first positioner that moves the frame in a first direction. The frame may also be attached to a second positioner that moves the frame in a second direction.
In accordance with a preferred embodiment of the present invention an optical sensor system is provided that detects movement of the at least one stylet and sheath, the optical sensor system being in electrical communication with the actuator system, wherein the actuator system controls movement of the at least one stylet and sheath in accordance with feedback received from the optical sensor system.
Further in accordance with a preferred embodiment of the present invention the optical sensor system includes a light source that illuminates at least one portion of the at least one stylet and sheath, and a camera that views and detects movement of the at least one portion.
Still further in accordance with a preferred embodiment of the present invention a mirror is mounted at an angle above the at least one portion of the at least one stylet and sheath, the mirror reflecting an image of the at least one portion towards the camera.